1. Field
One embodiment of the present invention relates to a method of manufacturing a magnetic recording medium such as a patterned medium.
2. Description of the Related Art
In a recoding medium wherein protrusions and recesses are formed on the surface thereof, such as a discrete track recoding (DTR) medium, in order to write and read by means of a flying head, it is necessary to reduce the protrusions and recesses on the surface to a degree which allows stable flying of the head. In a conventional DTR medium, in order to separate adjacent tracks completely from each other, for example, 20 nm of ferromagnetic recording layer and 5 nm of protecting layer, 25 nm in total, are removed. On the other hand, a flying level of the head is designed to be about 10 nm. Thus, there has been used a method to smooth the surface of the medium by filling the grooves with a nonmagnetic material, or to modify the non-recording region into nonmagnetic material without forming a construction of protrusions and recesses on the DTR medium.
In a method disclosed in Jpn. Pat. Appln. KOKAI Publication Nos. 2005-50468 and 2006-12332, after patterns of protrusions and recesses are formed by using two-layered hard mask, grooves are filled with a nonmagnetic material to smooth the surface of a medium. However, such a method may require increased number of steps of manufacturing, and can increase the cost and decrease the yield.
Moreover, in such a process that only modifies the non-recording region into a nonmagnetic material without forming a construction of protrusions and recesses, the boundary between the non-recording region and the recording region is fluctuated, which may be a cause of noise. At the same time, there is a problem how to modify the magnetism of the non-recording region without modifying the magnetism of the recording region.
Therefore, there has been a need for providing a method of manufacturing a recording medium which efficiently inhibits the magnetism of the non-recording region with minimum deterioration of the smoothness of the surface of the recording medium.